Portable hammer wrench



7 March 29, 1938.

v C N., DOUGLASS PORTABLE HAMMER WRENCH Filed June 16, 1937' 2 Sheets-Sheet 1 INVENTOR. '[Z-C/L /V. fiawmss I /7 BY ATTORNEY. I

March 29, 1938.

c, N. DOUGLASS PORTABLE HAMMER WRENCH 2 Sheets-Sheet 2 Filed June 16, 1937 INVENTCAJR. BY 647/4 M fiOflZASS ATTORNEY.

Patented Mar. 29, 1938 UNITED STATES PATENT OFFICE Application June '16, 1937, Serial-No. 148,427

Claims.

This invention relates to portable power operated hammer wrenches, and more particularly to improvements with respect to the hammer wrench disclosed and claimed in my copending 5 allowed application Serial No. 86,597, filed June 22, 1936 now Patent No. 2,086,261, granted July 6, 1937.

.One of the improvements contemplated relates to the provision of reversely acting pawl and about the spindle, to positively hold the spindle against a reverse rotation in the resetting of the driving pawl and ratchet mechanism following the blows of the pneumatic hammer on the impact collar. This is an improvement over the friction. clutch of the previous device in that a frictional connection will not positively hold the spindle against reverse rotation at all times in the resetting of the driving clutch.

Another improvement consists in holding th impact collar out. of peripheral contact with the wrench housing by riding the collar directly on the spindle. The advantages of this improvement are that the wrench housing isrelieved of the blows of the pneumatic hammer on the collar, and more power is assured as none of the energy is dissipated as heat by a frictional contact between the wrench housing and the periphery of the collar as in the previous construction. With n the impact collar riding on the spindle, it is essential that a positive interlock be provided as in the first mentioned improvement to hold the spindle against turning with the impact collar on resetting the driving clutch.

the cylinder for the plunger whichjurns the impact collar in its clutch resetting operation that live air pressure is entrapped in the cylinder to the rear of the plunger to insure an outward 40 operation of the wrench.

In the accompanying drawings illustrating the improvements referred to- Fig. 1 is a side view of the hammer wrench shown engaged with a nut to be operated upon, the nut engaging socket of the wrench being shown in section;

Fig. 2 is a longitudinal sectional view on a larger scale, with parts in elevation of the wrench end of the tool and the adjacent portion of the barr'el of the pneumatic hammer which operates the wrench, the view being taken on line 2-2 of Fig. 3; a

Fig. 315 a plan view of thewrench end of the tool, the cover section of the wrench housing ratchet mechanisms in the wrench construction A further improvement consists in so porting projection of the plunger at all times in the being omitted to show the pawl and ratchet mechanism for driving the spindle, the view showing a. portion of said'mechanism in section and taken approximately on line 3-3 of Fig. 4;

Fig. 4 is a vertical sectional view taken on line 44 of Fig. -2, showing the reversely acting pawl and ratchet mechanisms about the spindle as heretofore referred to; and

Fig. 5 shows the second pawl and ratchet mechanism in plan, partly in section, the entire view being taken on line 55 of Fig. 4.

The power wrench shown in the drawings, ex- I cept for the improvements herein described and claimed, is similar to the wrench construction disclosed in my co-pending application aforesaid and comprises generally a wrench housing I, a pneumatic hammer 2 secured to the wrench housing at one side thereof, a spindle 3 journaled in the wrench housing in roller bearings and in right angular relation to the pneumatic hammer, and a nut driving socket 4 enga-geable with either of the exposed ends of the spindle. The socket 4 has non-rotative, but releasable, connection with the ends of the spindle, the latter having at each end a spring biased detent 5- engageable in a recess in the socket as in the previous construction. -With the socket operable at either end of the spindle, nuts may be run on and oil of bolts without reversing the direction of rotation of the spindle. Hence, by merely reversing the position of the tool, the latter may apply and remove nuts by power.

A cap 6 fits over and encloses the end of the spindle not in use, This cap has detachable connection with the wrench housing about. the spindle, and not rotating with the spindle provides a hand rest for .the operator using the I I disposed anvil projection 8 on its outer periphery and ratchet teeth 9 on its inner periphery. Spring biased pawls l0 carried by the spindle co-operate witlrtheteeth 9 for rotating the spindle when the collar I is turned in one direction by the blows oi the hammer piston II on the anvil projection 8 of the collar. The teeth 9 are disposedcontinuously about the collar 1, and the pawls'arev circumferentially spaced as shown.

The arrow 17 in Fig. 3 indicates the direction in which thecollar l is turned to rotate the spindle. It will be observed from Fig. 3 that the pawls face this direction of rotation and have abrupt outer ends to abut the teeth 9 for a driving engagement. In the embodiment shown, five pawls II are employed .and each pawl has alternate driving engagement with the teeth 3 in the back and forth or oscillatory movement given' to the impact collar. With this arrangement, the third pawl from the driving one is at the top of its associate tooth so as to drop quickly into driving engagement with said tooth on turning the collar even though slightly with respect to the spindle.

The pawls II have their inner ends pivotally mounted on the spindle in semi-circular grooves II in the spindle and are pressed against the teeth 3 by coiled springs l3, also carried by the spindle, there being a spring-for each pawl. as

shown. The spindle is provided with bores I. to

accommodate the springs as detailed in Fig. 3.

The pawls II and the teeth 3 are co-extensive with the width of the impact collar providing a heavy duty driving clutch for the spindle 2. The grooves I! open through the spindle portion carrying 'the pawls enabling each pawl to be dropped into its' groove from an end thereof when assembling the device. This spin'dlepo'rtion is cut away or otherwise fashioned at its outer periphery to provi degspa'ces II for movement of the pawls inratcheting over the teeth of the collar I. This alsoproviduthe spindle portion with spokes II on the outer ends of which the collar'lridesatitsteethlasshowninl'ig. 3. These spokes have their outer ends concen trio with the axis of the spindle and'thus, the impact collar may ride on the spindle and be held thereby with its outer periphery out of contact with the enclosing wall I! of the housing I as lndicate'dby a clearancespace II in "Fig. 3.

The advantage of this as heretofore stated, is torelieve the wrench housing oi the blows of the hammer on the collar, and conserve power as none of the energy is dissipated as heat by frictional engagement between the periphery of thecollar and wrench housing as in theprevious construction.

The anvil projection 3 works in a chamber I! in the wrench housing and is engaged on its opposite sidesby a tappet "and a plunger 2 l shown in Fig. 2. The tappet 23 is carried by the barrel 3! of the pneumatic hammer and extends into the chamber I! for engagement with the anvil projection I as shown in Figs. 2 and 3. The tappet receives the blows of 'the hammer piston H, said piston being reciprocated back and forth in the barrel 22 by compressed air admitted alternately to the opposite ends of the barrel by the automatic action oi a distributing valve (not shown) in the V respectively, connected by an annular channel in the end of the barrel, as shown in Fig. 2. The passage 43 connects into the live air pressure valve section 23 of the hammer. g

The barrel-32 has screw threaded connection with the wrench housing in a tubular projection 24 thereon, a set screw 25 being employed .to hold the barrel against turning when the parts are assembled. The end of the tappet adjacent the anvil projection is beveled-0H as shown at 23 so thatv the tap t, will not strike against the .base of the projection where it Joinsthe collar This provides. for a rugged construction and permits the tappet to be brought relatively close to the collar soas to reduce the over-. all dimension of the assembly. The portion 21 of the tappet in the wrench housing has a nonrotative connection therewith to hold the tappet against rotation and thus keep the beveled end of the tappet in-proper relation to the collar. This non-rotative connection may be made by having the tappet and its receiving recess in the wrench housing square in cross-section with the covers on the tappeteut-oif as indicated at.

The impact collar. 1 is enclosed within the wrench housing being held against the bottom wall 23 of the chamber 30 for the collar by the I 4 the spindle 3 is journaled adjacent one end in the body portion of the wrench housing and adjacent its other end in the cover section 3|.

The second pawl and ratchet clutch about the spindle is shown in Fig. 5. This clutch comprises a ring 33 located in a chamber 33 in the cover portion 3| of the wrench housing immediately below the spindle portion carrying the driving pawls II. In practicethe ring 33 is held in its chamber 34 by the spokes it of the spindle overlapping the ring as shown in Fig. 4. The ring 33 is fixed to the wrench housing by a pin 35' as shownin Fig. 5. This holds the ring 33 against rotation and provides non-rotatlve support-for a number of spring biased pawls 33 extending inwardly from the inner periphery of the ring and operating in spaces 31 provided in the inner edge oiv the ring as shown. The pawls 33 aremounted' in grooves 33 in the ring and are pressed into of the spindle 3 surrounded by the ring by coiled springs 33. Thepawls 33 have abrupt outer ends and these ends abut against the teeth 39 to holdthe spindle 3 against reverse rotation when the impact collar 1 is turned to reset the drivlng pawls II. The pawls 33 ratchet over'the teeth 39 r when the spindle 3 is driven by these pawls. The reverse direction of'rotation referred to is in-' dicated by the arrow 0 in Fig. 5, audit will be noted that the pawls 38 are arranged to face-this direction. Six pawls 33 are spaced about the verse direction is prevented. With the impact collar 1 rotatably supported 25 engagement with ratchet teeth. on the portion ring 33 to alternately engage the teeth 39. .Hence, a slight rotation of the spindle in a reby the spindle 3 and riding directly on the spindle as heretofore stated, the impact collar byreason of its frictional engagement with the spindle would drag the spindle around with the collar exprovided by the second pneumatic hammer 2. The porting arrangement for this purpose follows the disclosure in my c.0- pending application, namely, having live air passages 33 in the wrench housing and barrel 22,:

ahead of the throttle valve 45 of the hammer. This by-passesthe live air about the throttle valve and insures a supply to the plunger 2| as soon as the air supply is turned on.

The air passage 43 in the wrench housing, as shown in Fig. 2, is connected into the cylinder 3| .betweenthe ends of the cylinder througha port 45. This port is closed by the-plunger ,II .on its return movement and live air will be entrapped behind the plunger to maintains pressure on the plunger. Hence, the plunger is prevented from going all the way back into the cylinder and becoming ineffective. The bore of the cylinder ll at its rear end is slightly larger than the diamwhen the plunger is at the bottom of the cylinder. The leak port is connected with a groove 48 in the exterior of the cylinder 4|, and this groove leads to a port 49 in the wrench housing connected with the passage 42 and the port 45, respectively.

The tool herein shown and described is-held in the hands of the operator the same as in the previous construction and will be used for runningon as well as running off nuts by power.

The wrench shown is of a size to apply and remove nuts from A" to 1%" diameter. For this size of wrench a pneumatic hammer is employed delivering approximately 1800 blows or strokes per minute. For a smaller size wrench blows as high as 4000 per minute may be used, while for a larger wrench the number of blows may be as low as 1200 per minute. The improvements disclosed add to the efiectiveness of the wrench and render the construction well adapted for the heavy duty work. In Fig. 1, the wrench is shown applied to a nut 50 on a bolt 5]. The socket l is shaped to fit the particular nut with which it is used. The pneumatic hammer provides a permanent handle member for the wrench.

The details of construction and arrangement of parts shown and described may be variously changed and modified without departing from the spirit and scope of my invention, except as pointed out in the annexed claims.

I claim as' my invention:

1. A portable power wrench comprising a housing, a rotary spindle journaled in the housing, an impact collar revolubly mounted in the housing about, the spindle and having an anvil projection, an intermittent grip device between the collar and the spindle for rotating the spindle when the collar is turned in one direction, a pneumatic hammer connected to the housing-and having a piston for imparting blows on the anvil projection for turning the collar in a direction to rotate the spindle, and means carried by the housing and operable on the collar in opposition to the piston for turning the collar in the opposite direction to reset the grip device following the blows of the piston on the collar, said housing having a chamber enclosing the collar and an impact collar revolubly mounted in the housing about the spindle and having ratchet teeth on its inner periphery and an anvil projection on its outer periphery, spring biased pawls carried by the spindle and cooperating with .said teeth for rotating the spindle when the collar is turned in one direction and for ratcheting over said teeth when the collar is turned in the opposite direction, a pneumatic hammer connected to the housing and having a'piston for. imparting blows on the anvil projection for turning the collar in a direction to rotate the spindle, and means carried by the housing and operable on the collar in opposition to the piston for turning the collar in the opposite direction to reset the pawls with respect to the teeth following the blows of the piston on the collar, said collar riding'at its teeth on the spindle and held thereby out of peripheral contact with the housing to the collar.

3. A portable power wrench comprising a lion ing, a rotary spindle journaled in the housing and v having a spoke-shaped portion, an impact collar revolubly mounted 'in the housing about the spoke-shaped portion of the spindle and having ratchet teeth on its inner periphery, spring biased pawls carried by the spokes of the spindle and cooperating with said teeth for rotating the spindie when the collar is turned in one direction and ratcheting over said teeth when the collar is turned in the opposite direction, a pneumatic hammer connected to the housing and having a piston for imparting blows on the collar for turning the collar in a direction to rotate the spindle, and means carried by the housing and operable on the collar in opposition to the piston for turning the collar in the opposite direction to reset the pawls with respect to the teeth following the blows of the pistonon the collar, said collar riding at its teeth on the outer ends of the spokes projection, a pawl and ratchet connection between the collar and the spindle for rotating the spindle when the collar is turned in one direction, a pneumatic hammer connected to the housing and having a piston for imparting blows on the anvil projection for turning the collar in a direction to rotate the spindle, means carried by' the housing and operable on the collar in opposition to the piston for turning the collar in the opposite direction to reset the pawl and ratchet connection between the spindle and the collar following the blows of the pistonthereon, said housing having a chamber enclosing the collar and said collar riding on the spindle and having a diameter less than the surrounding wall of the chamber whereby the spindle holds the ,collar out of peripheral contact with the housing, and a second pawl and ratchet mechanism in the housing about the spindle and cooperating therewith to positively hold the spindle against turning with the impact collar on'resetting the same.

5. A portable power wrench comprising a housing, a rotary spindle and an intermittent grip device for turning the spindle in one direction,

both journaled in the housing, said grip device having an impact collar about the spindle and provided with an anvil projection, a plunger and a tappet recipr'ocably mounted'in the housing on opposite sides of the anvil projection for contact therewith, a pneumatic hammer connected to the housing and having a piston for imparting blows on the tappet for turning the .collarin a direction to rotate the spindle, and means for subjecting the plunger to the live air pressure for A the hammer for forcing the plunger against the anvil projection to turn the collar in a direction to reset the grip device following the blows of the piston on the collar, said; means having an inlet port opened and closed by the plunger its back and forth movement to entrap live air behind the plunger to maintain a live air pressure thereon during the operation of the wrench.

- CECIL N. DOUGLASS. 

